Anyone who’s seen their share of movies knows the telltale signs when a supporting character is doomed. Whether they make a fatal mistake (like sleeping with James Bond) or have the bad luck to be the hero’s wife, police partner or mentor, the second you meet them, you know they’re not long for this world. Take one character in this weekend’s “The Expendables 2” (we won’t say which one), who seals his own fate by foolishly talking about his true love in the middle of an action movie. (Noooooo!)

Take note supporting film characters: These cliched situations will get you killed off in the movies quicker than you can say, “You’re the only one I’ve told.” (WARNING: SPOILERS ABOUND!)

  • 1. You’re the hero’s partner or best friend

    If you’re unlucky enough to be the partner of a cop in trouble, like Harrison Ford in “Witness” or Samuel L. Jackson in “The Negotiator,” consider your days numbered. Also, your untimely death might be one more thing to use to frame the hero. Sorry, partner! (See also: “In the Line of Fire,” “Unforgiven.”)

  • 2. You’re the hero’s wife

    Pity the poor woman who’s married to Maximus Decimus Meridius, whose death has to happen to set the rest of “Gladiator” in motion (as do the deaths of Mrs. Doc Ock in “Spider-Man 2” and Gerard Butler’s wife in “Law Abiding Citizen”). The silver lining of all this? Dead spouses have inspired some of cinema’s most elaborate, bloodthirsty revenge schemes. Case in point: The accompanying clip of Russell Crowe in “Gladiator.”

  • 3. You’re a hothead

    If you’re the heir to the Corleone family, you might get a bit cocky, as Sonny (James Caan) does in “The Godfather,” when he takes it on himself to publicly beat brother-in-law Carlo to a pulp. Unfortunately, this just speed ups his own demise on the highway in a famous hail of bullets. (Same goes for Joe Pesci in “Goodfellas,” who brings on his own whacking with an ill-advised offing of a made man.)

  • 4. You’re the only one(s) who can prove the hero’s real identity

    Once you go deep undercover (like John Travolta in “Face/Off” or Leonardo DiCaprio in “The Departed”), those few officials who know the truth about you are clearly going to be torched or thrown off a roof. <strong>(Clip NSFW)</strong>

  • 5. You just had sex with James Bond

    Ladies: If James Bond tries to seduce you to bring down your evil boss, just say no! It might be the best night of your life, but it’ll also be your last. After it happens, prepared to be fed to the sharks (“Dr. No”) or the dogs (“Moonraker”) or dipped in gold (“Goldfinger”) or crude oil (“Quantum of Solace”). Even someone as important to Bond as Vesper Lynd (“Casino Royale”) ended up getting the axe.

  • 6. You just had sex before marriage in a period film

    You’ve just found (or been reunited with) the love of your life and consummated your passion: Congrats! But now you must die, as Jude Law’s W. P. Inman found out in the Civil War epic, “Cold Mountain.”

  • 7. You’re a kid who’s too good to be true

    Did you cry over the deaths of Rue in “Hunger Games,” and Haley Joel Osment in “Pay It Forward?” Of course you did. It’s not fair when the young and idealistic are so brutally struck down, but it makes for great cinema. Well, sometimes: Some of us are still traumatized over Macaulay Culkin’s death by bees in “My Girl.”

  • 8. You’re in love

    Hey, love is dangerous. That soldier (Robert Sean Leonard) who shows his fiancee’s picture around and talks about how he can’t wait to get home to see her in “U-571”? So dead. (You just know the poor sucker is going to be one of the first to go at 1:40 in this clip.)

  • 9. You’ve just warned the hero that he needs to step it up

    Shortly after Jeff Daniels tells Keanu Reeves he won’t always be there to watch his back in 1994’s “Speed,” Jeff is blown to bits. (Excuse the random “Star Wars” Ackbar moment in this clip; it’s the only high-quality version of the scene we could find.)

  • 10. You tell the villain, “You’re the only one I’ve told.”

    Say you’re a hotshot cop with a lead, so you to go your superior to tell them your theory. When you’re asked, “Who else have you told,” answer, “Everybody!” Because if you say, “just you,” then you’re going to get blown away, just like a very surprised Colin Farrell does in “Minority Report.” (He really should have learned not to repeat Kevin Spacey’s “LA Confidential” mistake.)

  • 12. You’re in a Nicholas Sparks movie

    The guy has a formula. People fall in love, then people die: As Sparks’ fans have come to know, someone is guaranteed to bite it in every one of his stories. It could be the dad, it could be the romantic lead, or it could be the guy next door — just keep those tissues ready. (Example: Poor Mandy Moore in “A Walk to Remember.”)

  • 13. You’re Sean Bean

    Maybe it didn’t sink in for audiences until “Game of Thrones,” but this guy has made a career out of dying onscreen, as you can see in this final scene from the movie “Patriot Games.” (For further proof, check out the <a href=”http://www.youtube.com/watch?v=zEhtsgu6bJg&has_verified=1″ target=”_hplink”>Sean Bean Death Reel,</a> in which you can relive his deaths by cows, cave-ins, and Christian Bale.)

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Earlier on Moviefone: